Quasi-extruded felt



A ril 28, 1970 w. H. STICKNEY 3,509,014

QUASI-EXTRUDED FELT Filed Aug. 24, 1966 2, Sheets-Sheet 1 FIG.

"\1 THERMO STAT Coming Jacket INVENTOR. WENDELL H. STICKNEY hIS ATTORNEYS A ril 28 1970 w. H. STICKNEY QUASI-EXTRUDED FELT 2 Sheets-Sheet 2 Filed Aug.

INVENTOR.

WENDELL H. STICKNEY his ATTORNEYS United States Patent T 3,509,014 QUASI-EXTRUDED FELT Wendell H. Stickney, Springdale, Conn., assignor to GAF Corporation, a corporation of Delaware Filed Aug. 24, 1966, Ser. No. 574,766 Int. Cl. D02g 3/22 US. Cl. 161180 1 Claim ABSTRACT OF THE DISCLOSURE This invention relates to fiber-bonded felt-like materials. In order to produce elongated felt articles of this type of uniform cross-sectional shape, such as weather stripping, wicks for marking pens or the like, it has been customary to cut a length of felt from a sheet of felt material and then shape it by turning or by compression to the desired cross-sectional configuration. Moreover, short articles of identical cross-sectional shape such as felt washers have customarily been produced by stamping them out of sheet material. Such procedures are not only wasteful of material but also, because of the compression or working of the material, produce articles having non-uniform fiber distribution and, therefore, having lower liquid absorption or higher density than is desirable in many cases.

Heretofore, attempts have been made to produce felt articles of uniform cross-sectional shape by various operations on a continuous rope of material but all the previous attempts have been subject to serious disadvantages. It has been proposed, for example, to treat all of the fibers in a strip of continuous filamentary tow material with plasticizer, then form the plasticized strip into a rope and finally pass the rope into a shaping die while heating it with penetrating steam jets. Articles made in this manner, however, have a reduced absorption capacity and a nonuniform fiber distribution because the generally parallel fibers of the strip are easily packed together during passage through the die and also because groups of internal plasticized fibers adhere together to form solid lumps or slivers. In particular, the ink capacity of marking pen wicks produced in this manner is reduced to a relatively low value.

An object of the invention is to provide new and improved felt articles of uniform cross-sectional shape characterized by their low density and uniform internal fiber distribution.

An additional object of the invention is to provide a new and improved wick for marking pen reservoirs and the like having a substantially increased capacity.

These and other objects of the invention are attained by forming a roving containing some binder fibers which become adherent at an elevated temperature and other fibers which will not be rendered adherent at the temperature at which the binder fibers become adherent. As used herein, the term roving means any continuous length of staple fibrous'material. The roving is drawn through a heated die having the desired cross-sectional configuration of the article, the die temperature being high enough to render the binder fibers adherent, and then through a cooler die portion having the same configuration. Preferably, the proportion of binder fibers in 3,509,014 Patented Apr. 28, 1970 the roving is within the range from about one-fifth to about one-half and, in a particular embodiment used to prepare marking pen wicks, the binder fiber comprised 30 to 40% of the roving. A preferred binder fiber material is plasticized cellulose acetate.

To form a marking pen wick, the die is of generally circular configuration with a longitudinal inward projection so that the continuously formed wick has a groove extending along its outer surface to provide an air vent. Furthermore, the ends of the improved wick of the present invention are rounded by heating them for a short time in another die member which does not engage the central portion of the wick.

Further objects and advantages of the invention will be apparent from a reading of the following description in conjunction with the accompanying drawings in which:

FIG. 1 is a view in elevation, partly schematic, illustrating a representative embodiment of the method for making felt materials according to the invention;

FIG. 2 is an enlarged cross-sectional view taken on line 22 of FIG. 1 and looking in the direction of the arrows;

FIG. 3 is a cross-sectional view illustrating a further step in the manufacturing of felt marking pen wicks according to the invention;

FIG. 4 is a side view of a marking pen wick made in accordance with the invention; and

FIG. 5 is an end view of the wick shown in FIG. 4.

In the representative method of making felt materials according to the invention which is illustrated in FIG. 1, a rope 10 of a fiber which has been prepared in roving form as, for example, on a conventional carding machine without a Peralta roll, is conveyed from a supply barrel 11 up over a feed capstan 12 and down into a vertically oriented heating tube 13. The roving 10 consists of a mixture of synthetic binder fibers, such as cellulose acetate to which a plasticizer has been added, which becomes adherent when heated to a temperature in the range from 200 to 400 R, for example, and other fibers, either natural or synthetic, which do not become adherent at that temperature.

One preferred type of binder fiber is Estron Plasticized Acetate Staple I, manufactured by Eastman Chemical Products, Incorporated, although other binder fibers having similar properties may be used. For example, the synthetic fiber known as Vinyon No. 997 may be used. Preferably, the proportion of binder fibers is in the range from about one-fifth to one-half, but larger or smaller proportions of binder fiber may be used depending upon the nature and intended characteristics of the felt material being made. The remaining fibers of the roving may be of any synthetic or natural material otherwise suitable for the felt article being made, such as unplasticized acetate, wool, cotton, or polyester for example, and all of the fibers may be of various conventional staple lengths. Uniformity of the blend in the roving assures good quality of the finished product.

The heating tube 13 comprises an inner tube member 14 having a diameter somewhat larger than the thickness of the roving, for example, 2 inches, a co-axial outer tube member 15 of larger diameter, and four pairs of ringshaped electrical heating elements 16, best seen in FIG. 2, which are embedded in a fiberglass insulating layer 17 confined between the two members 13 and 14. The heating tube is long enough to assure heating of at least the outer portion of the roving to a temperature sufficient to render the binder fibers therein adherent and may, for example, be about three feet long.

Each of the heating elements 16 is connected through a thermostat 18 to an electrical power source 19, the thermostat being responsive to a temperature sensitive element 20 located adjacent to the inner tube member 14 near the lower end of the heating tube. In addition, a thermometer 21 is mounted-at thesame'location to provide a visual indication of the internal temperature of the tube. The thermostat 18 is arranged to maintain the temperature ofthe tube, as indicated by the'thermometer 21, high enoughto. assure softening of thebinder fibers at the surface of the roving and, .ingeneral, the indicated .temperaturcs :at the thermometer 21 will be, for example, v about 100 higher than the temperature of the roving.

Immediately below the, thermometer 21. and within -the lowest pair of heating'ringslti, a. die member 22'has a generally conical converging opening .23 leading'downwardly to a centralpassagewayl-having the .desired reason, the die passageway 24 should be slightly smaller than the desired cross-section of the finished article.- Typically, the amount of expansion; may-be about five percent. Inorder to assure that the felt article being formed will maintain the desiredcross-sectional shape, the die 22 includes a coolingportion 25 having the same internal configuration as the passageway 24 and extending downwardly from the bottom end of the heating tube 13, which rests on a table 26. Preferably, to assure rapid setting of the binder fibers, a cooling jacket 27 is provided about the cooling portion 25 and cold water is circulated therethrough. As the formed felt material passes through the cooled die extension 25, it is held in the desired shape until the binder fibers become firm.

After leaving the die, the formed elongated felt material passes between two drive rolls 28 which serve to draw the material through the apparatus at a controlled rate, which may be several feet per minute, depending upon the characteristics of the material and the tempera ture of the tube 13 and other factors. Thereafter, a cutting blade 29 severs the formed continuous felt material are uniformly distributed throughout the interior of the finished article in substantially non-adherent relation, i.e., without any hard lumps or slivers. The depth of the hardened outer layer may be controlled by regulating the rate of motion of the roving through the die in conjunctionWith' the die temperature and the plasticization of the binder fibers so that'the appropriate rate of heat transfer to produce binder fiber softening at the desired depth is "obtained; Furthermore, because many of the fibers of the roving'10' are distributed in orientations transverse to the length of the'roving, instead of extending generally paral-" lel; to its length as is the case with tow fibers, for example, the spacing of the fibers in the interior ofythe finished article'a'ccording to the invention is considerably mor uniform than canbe accomplished otherwise.

/ ..In' accordance with another aspect ofthe invention, the method described above is'used to prepare felt markingpen ink reservoirs of novel and advantageous eonfiguration.v For this purpose, as shown in FIG..2, the

die 22 is provided with an internal passageway 24 having an inwardly projcctingzridge 31' extending longitudinally.

along one side of" the passageway. As shown in FIGS.

3, 4 and'S', this ridge produces alongitudinally extending groove molded in. the outer surface's of the finished wick having a'-depth"qual" to'about one-tenth of the diameter of the wick. This groove 32 servesas an escape passage- .Way for air asth'e reservoir containing the wick is filled with ink, thereby permitting more rapid filling and as- --suringcompletefilling. In the absence of -this air escape passageway, air must pass between the fibers of the wick so as to impede filling of the reservoir and some air is likely to be trapped at the inner end of the reservoir as itisfilled,

furthermore, to facilitate in'sertion of the'wickfi'into a reservoirhavin'g: the same diameter or evenafsli'ghtly smaller diameterthan the wick, the ends"33 of the-wick are rounded about their. outer periphery by inserting them into a die'34 having an electrical heatingcoil 35 and an internal cavity-formed with a roundeclouter portion 36 and an open inner portion 37. The e'ndof the wick is held against the rounded portion 35 just-long enough to soften the plasticized fibers sufficiei'itly to make them conform to the rounded shape. In this way,"the rounded ends 33 are provided without heating the fibers in the central portion. 38 of the vwick sufficiently to soften them which would tend to seal "the e'nd'of'the wick, the open centralportion 38 having a diameter equal to about half to three quarters that of the wick. Consequently, the How of ink from the internal fibers 'in the end portion to the writing nib which engages that portion will not be impeded. Also, with wicks having these rounded ends, automatic loading of reservoirs with wicks is feasible.

Furthermore, by using a roving'conta'ining a mixture of binder fibers with nonsoft'ening fibers, the wick '30 of the present invention is made so that the internal fibers are more uniformly spaced and generally are not adhered together. Because of the larger proportion of passages of the proper capillary dimension, the wick has a greater ink capacity than other wicks but, at the same time, occupies substantially all of the reservoir volume,

In a particular example according to the invention, a roving consisting of about 60 to percent 3.0 denier non-textile acetate and about 30 to 40 percent Estron Plastici'zed Acetate Staple I and having a weight of about 30 grams-per yard was made by passing the fibers twice through a fiber opening and blending machine and then carding them' on a conventional card'without a Per'alta roll. This roving was drawn through a forming apparatus of the type shown in FIGS. 1 and 2, at a rate of about three feet per minute with the thermometer 21 indicating about 375 F. The internal diameter of the heating tube 13 was two inches and the diameter of the passageway 24- was 0.562 inch. Cooling water at"35 F. was circulated through the cooling jacket 37 at a rate of one-half gallon per minute. Thecontinuous wick produced by this method had a diameter of 0.591 inchand weighed 22 grams per yard, the roving having been elongated about 15 percent in the drawing process.

Although the invention has been described herein 'With reference to specific embodiments, many modifications and variations therein will readily occur'to those skilled in the art. For example, rather than being generally round, the felt material prepared according to the invention may have an irregular cross-sectional configuration, such as an L-shape. Moreover, articles'with central apertures such as washers may be formed by supporting an appropriate elongated hole-forming member centrally within the passagewa'y'24 of the heated die. Accordingly, all such variations and modifications are included within the intended scope of the inventionas defined by the following claim;

I claim: 1. A felt article adapted for use as a liquid reservoir -within' aholder comprising an along'ated generallycircular cylindrical fibrous "member formed with a longitudinal groove along at least one side and having rounded end portions, between about oiie-fifth and about one-half of the fibrous material in the member being binder fibers adapted to becomeadherent atafselectedelevated temperature and the remainder bein'g' other "fibers which" do not become adherent at the selectedelevated temperature, afsnb'stantial proportion of the binder fibers about. the periphery of the reservoir being adhered to other fibers 5 6 with which the binder fibers are in contact and substan- 3,050,768 8/1962 Rosenthal 401-499 tially fewer of the binder fibers within the interior of 3,094,736 6/ 1963 BlIIlZl 6181- 01198 the reservoir being adhered to other fibers with which the binder fibers are in contact. FOREIGN PATENTS 5 1,444,361 5/1966 France. References Cited UNITED STATES PATENTS ROBERT F. BURNETT, Prlmary Examiner L. M. CARLIN, Assistant Examiner 2,500,282 3/1950 Francis 161170 X 2,688,380 9/1954 MacHenry 401-198 X 10 US. C1.X.R.

2,979,433 4/1961 MacHenry. 161150; 401196 

